The present invention relates to a variable displacement pump, a valve timing control device using the variable displacement pump, and a valve timing control system using the variable displacement pump, for use in internal combustion engines.
Japanese Patent Application First Publication No. 2002-371811 discloses a valve timing control device for internal combustion engines which is of a so-called vane type and includes a phase-advance hydraulic chamber and a phase-retard hydraulic chamber which are separated from each other within a housing by a partition portion of the housing and a vane member with a plurality of blades. The vane member is rotated in a positive rotation direction or a negative rotation direction to thereby selectively conduct supply and discharge of an oil pressure fed from an oil pump that is driven by an internal combustion engine, with respect to the phase-advance hydraulic chamber and the phase-retard hydraulic chamber. The valve timing control device thus variably controls an open-and-closure timing of an engine valve depending on an engine operating condition.